The present invention deals with fiberscopes useful in medical, veterinary and industrial applications using bundles of optical fibers to illuminate and to transmit images of remotely located objects.
Because of the nature of glass fibers (numerical aperture), it is frequently necessary to utilize a lens or lens system at the distal or objective end of light guide fiber optic bundle to spread light providing illumination for the imaging view.
In most fiberscopes the various light guide and imaging bundles are received and anchored within a metallic element known as an objective head.
The metallic head is machined to provide recesses and appropriate through bores to accommodate fiber bundles and to provide outlets for the usual and customary utility channels such as air, water, suction, biopsy instruments and the like.
The required lenses, usually of glass, are individually manufactured at relatively high cost because of their small size, i.e., 1 to 2 mm. in diameter by 0.75 to 1.0 mm. thick.
These small glass objects are cemented into machined counterbores in the metallic head.
A representative example of prior art is disclosed in U.S. Pat. No. 4,266,534 issued May 12, 1981, to Mototogu Ogawa and assigned on its face to Olympus Optical Co., Ltd., Tokyo, Japan. In this disclosure a variety of lenses 6 are shown cemented to machined counterbores in a metallic objective head.
The problem with prior art lens settings is the risk and the dangerous consequences of a lens falling out of its setting and detaching from the instrument during a critical medical, veterinary or industrial procedure.
Another problem with prior art objective heads is the expense of manufacture.
A still further problem with the prior art device is its ability to conduct electricity. Since various electrical power sources are associated frequently with modern fiberscopes, it has become necessary to provide electrical grounds to insure against injury resulting from random or stray currents transmitted through a metallic head.